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Commit 3d8598fb authored by Tero Kristo's avatar Tero Kristo
Browse files

clk: ti: clkctrl: use fallback udelay approach if timekeeping is suspended 



In certain cases it is possible that the timekeeping has been suspended
already when attempting to disable/enable a clkctrl clock. This will
happen at least on am43xx platform when attempting to enable / disable
the clockevent source itself, burping out a warning from timekeeping core.

The sequence of events leading to this:
-> timekeeping_suspend()
 -> clockevents_suspend()
  -> omap_clkevt_idle()
   -> omap_hwmod_idle()
    -> _omap4_clkctrl_clk_disable()
     -> _omap4_is_timeout()

Avoid the issue by checking if the timekeeping is suspended and using
the fallback udelay approach for checking timeouts.

Signed-off-by: default avatarTero Kristo <t-kristo@ti.com>
Acked-by: default avatarStephen Boyd <sboyd@codeaurora.org>
parent 5b385a45

drivers/clk/ti/clkctrl.c

+13 −1
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/of_address.h>

#include <linux/clk/ti.h>

#include <linux/delay.h>

#include <linux/timekeeping.h>

#include "clock.h"



#define NO_IDLEST			0x1
@@ -90,7 +91,18 @@ static bool _omap4_is_ready(u32 val) 


static bool _omap4_is_timeout(union omap4_timeout *time, u32 timeout)

{

	if (unlikely(_early_timeout)) {

	/*

	 * There are two special cases where ktime_to_ns() can't be

	 * used to track the timeouts. First one is during early boot

	 * when the timers haven't been initialized yet. The second

	 * one is during suspend-resume cycle while timekeeping is

	 * being suspended / resumed. Clocksource for the system

	 * can be from a timer that requires pm_runtime access, which

	 * will eventually bring us here with timekeeping_suspended,

	 * during both suspend entry and resume paths. This happens

	 * at least on am43xx platform.

	 */

	if (unlikely(_early_timeout || timekeeping_suspended)) {

		if (time->cycles++ < timeout) {

			udelay(1);

			return false;